Sulforaphane-mediated immune regulation through inhibition of NF-kB and MAPK signaling pathways in human dendritic cells

Inflammation and immune responses are intricately intertwined processes crucial for maintaining homeostasis and combating against pathogens. These processes involve complex signaling pathways, notably the Nuclear Factor kappa-light-chain-enhancer of activated B-cells (NF-κB) and Mitogen-Activated Protein Kinase (MAPK) pathways, which play crucial roles. Sulforaphane (SFN), a nutraceutic, has emerged as a potential regulator of NF-κB and MAPK signaling pathways, exhibiting anti-inflammatory properties. However, limited knowledge exists regarding SFN's effects on immune cell modulation. This study aimed to assess the immunomodulatory capacity of SFN pretreatment in human dendritic cells (DCs), followed by exposure to a chronic inflammatory environment induced by lipopolysaccharide. SFN pretreatment was found to inhibit the NF-κB and MAPK signaling pathways, resulting in phenotypic changes in DCs characterized by a slight reduction in the expression of surface markers, as well as a decrease of TNF-α/IL-10 ratio. Additionally, SFN pretreatment enhanced the proliferation of Treg-cells and promoted the production of IL-10 by B-cells before exposure to the chronic inflammatory environment. Furthermore, these changes in DCs were found to be influenced by the inhibition of NF-κB and MAPK pathways (specifically p38 MAPK and JNK), suggesting that these pathways may play a role in the regulation of the differentiation of adaptive immune responses (proliferation of T- and IL-10-producing regulatory-cells), prior to SFN pretreatment. Our findings suggest that SFN pretreatment may induce a regulatory response by inhibiting NF-κB and MAPK signaling pathways in an inflammatory environment. SFN could be considered a promising strategy for utilizing functional foods to protect against inflammation and develop immunoregulatory interventions.